Rescue drill just 100m from reaching Chilean miners
Published 08/10/2010 | 05:00
The 33 miners trapped 2,297ft below the Atacama Desert are being prepared for rescue as the drill boring the shaft to reach them is expected to break through within hours.
The Schramm T-130 drill has started drilling the final 330ft (100m) to widen a borehole for a metal rescue capsule that will raise the men from the deep chamber where they have been trapped since August 5.
Laurence Golborne, Chile's mining minster, announced yesterday that he expected the breakthrough to come early tomorrow. The men could be lifted to the surface as early as Monday.
"We are advancing pretty well," Mr Golborne said. "We are hoping to break through more or less by day-break this Saturday but, depending on whether we have to change the hammer or not, it could be a little earlier."
The team of engineers must then decide how much, if any, of the 2,067ft borehole needs to be lined with metal casing, a process that could extend the miners' confinement for another eight to 10 days.
The casing would serve to reinforce the walls of the shaft, limiting the risk of collapse, and would also act as buffer between the capsule and the shaft resulting in a smoother journey to the surface.
"The final decision [on the casing] will be taken once we have broken through," Mr Golborne said. "If none is needed it could take two-to-three days depending on installation of the rescue platforms."
Experts warned that inserting the lining could be a challenge as the shaft curves between the depth of 330ft and 395ft.
A winch capable of lifting 400 tonnes must be installed on a platform over the shaft to lower in the tubing, but an accident could send tons of steel hurtling downwards or cause a section to get stuck part way down, blocking an exit route that has taken more than a month to drill.
"It seems likely that we will have to put in the casing at least for the first 330ft," said Rene Aguilar, the rescue co-ordinator. "If we could do the lining for all the hole, of course, we are going to do it. We have to reduce the risk of this operation."
Family members have been briefed of the decision-making process. "We want to have the shaft lined if that seems safer," said Juan Carlos, the nephew of Jose Ojeda, a trapped miner. "We have been waiting for so long that one or two more days is nothing."
When rescue day arrives, the miners will be brought to the surface in a bullet-shaped pod designed by the Chilean navy's shipyards and dubbed 'Phoenix'. (©Daily Telegraph, London)